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Re: HT-37 transformer failure due to rapid STBY-->OFF-->STBY
开云体育Halden, this is rather late too Re ?your comments in [quoted text] and ?pics? in ???/g/HallicraftersRadios/message/30775 ? I Halden, I see it much the way you describe, but ?we don’t know the core’s B-H curve, and would suggest that it is not saturating badly[it is not hard saturation], but “saturation” is such a loose thing. ??The current peak ?is well behind the voltage, so there is still quite a bit of permeability left in the core, but it must be into the saturating region[my term] If it had really saturated [only resistance left] the current would be in phase with the voltage. That current lag seems to continue down to? current zero, then the negative current peak is very close to the voltage. I don’t think you will find many power transformer cores saturating badly, but there will be gentle saturation, but those switching cores[hard cores] are another matter. When I say power transformer, I mean, any transformer intended to efficiently transfer power at 50/60Hz, wheather it is down near say 30 VA or up above 300 MVA. Please excuse all these ”I”s, but I don’t want to imply that I have access to the bible. But Halden, I keep wondering about the 49 Amps you said, you mentioned a 1 ohm resistor, I thought, so I get 24 amps peak. Maybe you changed it to a half?? ?? ? From: [email protected] [mailto:[email protected]] On Behalf Of HF via groups.io
Sent: Thursday, August 8, 2024 12:38 PM To: [email protected] Subject: Re: [HallicraftersRadios] HT-37 transformer failure due to rapid STBY-->OFF-->STBY ? Here's an interpretation of the surge according to the theory that it represents the transformer core reaching saturation. In image #49, which shows the strong surge, one can see that the current waveform started normally, using image #58 as a reference.? The core had not reached a non-linear point as the current started to flow.? At about 45 degrees into the cycle, it reached a slightly non-linear region and increased at a higher rate until almost 90 degrees into the cycle.? At that point, the core reached saturation, but the applied voltage was still positive.? Then, there was no additional magnetizing that the current forced by the voltage could do.? Lacking such impedance to its flow, the current surged until there was no more voltage available to drive it.? At that point, the inductive nature of the primary winding maintained the current flow as the voltage reversed polarity.? This current took another cycle or two to fall back to zero.? Meanwhile, the negative applied voltage drove the core back out of saturation and partly towards the opposite magnetization polarity.? The next cycle began with the core less magnetized than the first, so the core didn't go as far into the saturation zone that time.? Did I get this right? Cheers, Halden _._,_._,_ -- don??? va3drl |
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Re: HT-37 transformer failure due to rapid STBY-->OFF-->STBY
From: [email protected] [mailto:[email protected]] On Behalf Of Jim Whartenby via groups.io ? Don I am not posting here to argue, ?????if you are referring to ?my“for the sake of argument”, In my world that means?? ?“to propose something so we can discuss it” [or argue politely about THAT TOPIC]. ??I’m sorry if I was too unclear. Perhaps that is colloquial? From the web: What does for the sake of the argument mean? It means that you don't believe that the thing you are about to say is necessarily true, but you are saying it to explore a hypothetical situation. For example, you might say: "Let's assume, for the sake of argument, that you start the building work in June.Oct 1, 2018 ? ????????? I am trying to understand what the posted data means and how it adds to the understanding of the HT-37 power transformer failure.??Me too So far, there was almost no information given on how the power transformer was tested, what type of loads were placed on the windings during tests, and so on.??? I am reluctant to comment on now much needs to be written; what is too much and what is too little? ? Without this information, I don't see how any of the o'scope images are of any use.? I have managed to fill in the gaps, but I have spent a few years looking at real CRT’s starting with an EICO 460 kit when I was in grade 11, but any readers that don’t have much scope time, would be at a disadvantage. ?When I have asked, what I thought were legitimate questions, I get replies full of rebuttals and wild guesses on what might be causing what was presented.? This has led to several off topic replies from this end.? Sorry about that chief. ???The old school said re-read/write 3 times and I say with breaks between before sending. After getting it “off your chest”? one might decide to tame it down or clarify something, etc etc ?and fix the Auto-mutilate hits ?before sending. AI will soon complete your hole sentence after 3 words. ? I have learned a lot while debunking these guesses and I now realize that I have made some wrong assumptions on how a transformer actually works.? Apparently I got lost wading through the weeds. ? Rather than make a new posting about the half turn stuff, I hope you read it first. It is sneaky stuff , that is made more clear in another article, that thing called a “half-turn”? is physically a whole turn around half the main core of a shell type transformer, if you split the core into 10 cores you could make “tenths of a turn” on a secondary only.. a good school project. ? From: [email protected] [mailto:[email protected]] On Behalf Of Jim Whartenby via groups.io ? Don I am not posting here to argue, I am trying to understand what the posted data means and how it adds to the understanding of the HT-37 power transformer failure.??So far, there was almost no information given on how the power transformer was tested, what type of loads were placed on the windings during tests, and so on.?? ? Without this information, I don't see how any of the o'scope images are of any use.? When I have asked, what I thought were legitimate questions, I get replies full of rebuttals and wild guesses on what might be causing what was presented.? This has led to several off topic replies from this end.? Sorry about that chief. ? I have learned a lot while debunking these guesses and I now realize that I have made some wrong assumptions on how a transformer actually works.? Apparently I got lost wading through the weeds. Regards, Jim Logic: Method used to arrive at the wrong conclusion, with confidence.? Murphy ? ? On Sunday, August 11, 2024 at 08:41:34 PM CDT, don Root <drootofallevil@...> wrote: ? ? Jim they are both right, but for the sake of argument the in-phase is right, and it is right for a long time, but when the switch closes there is a good chance that the combination of left over flux, and switch closing angle will try to drive the flux past the normal peak and when things go to one extreme the core saturates extremely. In which case the inrush is so big that it swamps the load current, but likely when it is real high the transformer is no longer a “transformer”. I’m not sure it I the same image, but on one you could see the small load current partially ?going to the right, but at the left you see the load current rise then the ?inrush swamps the waveform., so it was not the worst case. If the transformer was really left saturated, the current would shoot up with no delay with the voltage. I recorded a 30X inrush on a Honeywell visicorder. That core was being driven very hard. Too many volts per turn. That was a early class H potted transformer, maybe 25 or 50 kVA. Fusing as a real problem for it. ? From: [email protected] [mailto:[email protected]] On Behalf Of Jim Whartenby via groups.io ? OK, back to the beginning. Some of Halden's scope images show the transformer's primary current in phase with the voltage across the primary, a few show a 90 degree phase difference with voltage leading current by 90 degrees.? Which is right? Jim
_._,_._,_ -- don??? va3drl |
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Re: HT-37 transformer failure due to rapid STBY-->OFF-->STBY
Don I am not posting here to argue, I am trying to understand what the posted data means and how it adds to the understanding of the HT-37 power transformer failure.??So far, there was almost no information given on how the power transformer was tested, what type of loads were placed on the windings during tests, and so on.?? Without this information, I don't see how any of the o'scope images are of any use.? When I have asked, what I thought were legitimate questions, I get replies full of rebuttals and wild guesses on what might be causing what was presented.? This has led to several off topic replies from this end.? Sorry about that chief. I have learned a lot while debunking these guesses and I now realize that I have made some wrong assumptions on how a transformer actually works.? Apparently I got lost wading through the weeds. Regards, Jim Logic: Method used to arrive at the wrong conclusion, with confidence.? Murphy
On Sunday, August 11, 2024 at 08:41:34 PM CDT, don Root <drootofallevil@...> wrote:
Jim they are both right, but for the sake of argument the in-phase is right, and it is right for a long time, but when the switch closes there is a good chance that the combination of left over flux, and switch closing angle will try to drive the flux past the normal peak and when things go to one extreme the core saturates extremely. In which case the inrush is so big that it swamps the load current, but likely when it is real high the transformer is no longer a “transformer”. I’m not sure it I the same image, but on one you could see the small load current partially ?going to the right, but at the left you see the load current rise then the ?inrush swamps the waveform., so it was not the worst case. If the transformer was really left saturated, the current would shoot up with no delay with the voltage. I recorded a 30X inrush on a Honeywell visicorder. That core was being driven very hard. Too many volts per turn. That was a early class H potted transformer, maybe 25 or 50 kVA. Fusing as a real problem for it. ? From: [email protected] [mailto:[email protected]] On Behalf Of Jim Whartenby via groups.io
Sent: Sunday, August 11, 2024 8:13 PM To: [email protected] Subject: Re: [HallicraftersRadios] HT-37 transformer failure due to rapid STBY-->OFF-->STBY ? OK, back to the beginning. Some of Halden's scope images show the transformer's primary current in phase with the voltage across the primary, a few show a 90 degree phase difference with voltage leading current by 90 degrees.? Which is right? Jim ? -- don??? va3drl |
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Re: HT-37 transformer failure due to rapid STBY-->OFF-->STBY
Don "Abstract—The half-turn effect is present in transformers if the
winding leads are taken out from the different sides of the core.
The result is an additional half-turn in one of the core windows
in a single-phase transformer, which can create overfluxing of the
core leading to excessive losses and temperature rises. This paper
presents a methodology to analyze the half-turn effect in power
transformers....." The above found in:?? AFAIK, fractional transformer turns smaller then a half turn can only be implemented in certain styles of ferrite core high frequency transformers operating above 50kHz.? Not possible to do in iron core transformers. Jim Logic: Method used to arrive at the wrong conclusion, with confidence.? Murphy
On Sunday, August 11, 2024 at 08:05:43 PM CDT, don Root <drootofallevil@...> wrote:
Ooops ?sorry that was a copy of Jims post enlarged so I could read it I will delete it on line later Jim if you are going to measure the volts or amps , you need a meter and two leads, and then the leads somehow go to the core, and perhaps it is a whole turn, then you cut it to a half turn, and ? ?and 1/8 th turn, and then a 0.00005 turn and finally no turn, I’ll bet your meter reads the same. In the final test the leads go around the core and join and the meter leads become the whole turn. ??I don’t think that was apparent when ?? did his first experiments but ?础尘辫è谤别 ??or Faraday spoke about the closed loops. ? You can make a super micro-mini- meter anf put it right at your half turn, but to get any volts they have to extend ?the two ? turn leads around the core to reach your half turn, and that makes one whole conductive turn. ?I have never been able to walk up half-a-step either.. frustrating stuff If you don’t finish the turn the laws mean nothing, ? From: [email protected] [mailto:[email protected]] On Behalf Of Jim Whartenby via groups.io
Sent: Sunday, August 11, 2024 7:34 PM To: [email protected] Subject: Re: [HallicraftersRadios] HT-37 transformer failure due to rapid STBY-->OFF-->STBY ? Don In a transformer, a half turn starts on one side of the laminated core and exits on the other.? Since the Weller has that plated copper tube entering the core on one side and exiting the core on the other, it is by definition, a half turn.? It does not matter if the tube wraps around the outside of the lamination, it is still a half turn through the core.? If a winding makes one full wrap around the core that holds the primary and exits on the same side that it entered, then it is a full turn.? If you measure the open circuit voltage of the Weller soldering gun tube, it should be approximately a quarter volt.? That tube allows about 100 VA to be transformed to about 400 amps @ 0.25 volt! ? As long as you can fit an insulated wire between the bobbin and the laminations and make a full turn as in above then you can determine the turns-per-volt of any power?transformer.? I prefer 10 turns, make the measurement and then divide it by 10 but you can do as you like.? You must have a transformer or two in your junk-box so it should be easy to verify this procedure. ? Typically one strips off only the secondary windings and keeps the primary intact.? Knowing the voltage produced by a high current heater winding and counting the turns will give the same result for the turns-per-volt of that particular transformer.? Then wind as many turns as needed to get the output voltage wanted in the secondary windings.? This was one of the first lab experiments in college for transformers in AC circuits. Regards, Jim -- don??? va3drl |
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Re: HT-37 transformer failure due to rapid STBY-->OFF-->STBY
开云体育Jim they are both right, but for the sake of argument the in-phase is right, and it is right for a long time, but when the switch closes there is a good chance that the combination of left over flux, and switch closing angle will try to drive the flux past the normal peak and when things go to one extreme the core saturates extremely. In which case the inrush is so big that it swamps the load current, but likely when it is real high the transformer is no longer a “transformer”. I’m not sure it I the same image, but on one you could see the small load current partially ?going to the right, but at the left you see the load current rise then the ?inrush swamps the waveform., so it was not the worst case. If the transformer was really left saturated, the current would shoot up with no delay with the voltage. I recorded a 30X inrush on a Honeywell visicorder. That core was being driven very hard. Too many volts per turn. That was a early class H potted transformer, maybe 25 or 50 kVA. Fusing as a real problem for it. ? From: [email protected] [mailto:[email protected]] On Behalf Of Jim Whartenby via groups.io
Sent: Sunday, August 11, 2024 8:13 PM To: [email protected] Subject: Re: [HallicraftersRadios] HT-37 transformer failure due to rapid STBY-->OFF-->STBY ? OK, back to the beginning. Some of Halden's scope images show the transformer's primary current in phase with the voltage across the primary, a few show a 90 degree phase difference with voltage leading current by 90 degrees.? Which is right? Jim ? -- don??? va3drl |
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Re: HT-37 transformer failure due to rapid STBY-->OFF-->STBY
开云体育Ooops ?sorry that was a copy of Jims post enlarged so I could read it I will delete it on line later Jim if you are going to measure the volts or amps , you need a meter and two leads, and then the leads somehow go to the core, and perhaps it is a whole turn, then you cut it to a half turn, and ? ?and 1/8 th turn, and then a 0.00005 turn and finally no turn, I’ll bet your meter reads the same. In the final test the leads go around the core and join and the meter leads become the whole turn. ??I don’t think that was apparent when ?? did his first experiments but ?础尘辫è谤别 ??or Faraday spoke about the closed loops. ? You can make a super micro-mini- meter anf put it right at your half turn, but to get any volts they have to extend ?the two ? turn leads around the core to reach your half turn, and that makes one whole conductive turn. ?I have never been able to walk up half-a-step either.. frustrating stuff If you don’t finish the turn the laws mean nothing, ? From: [email protected] [mailto:[email protected]] On Behalf Of Jim Whartenby via groups.io
Sent: Sunday, August 11, 2024 7:34 PM To: [email protected] Subject: Re: [HallicraftersRadios] HT-37 transformer failure due to rapid STBY-->OFF-->STBY ? Don In a transformer, a half turn starts on one side of the laminated core and exits on the other.? Since the Weller has that plated copper tube entering the core on one side and exiting the core on the other, it is by definition, a half turn.? It does not matter if the tube wraps around the outside of the lamination, it is still a half turn through the core.? If a winding makes one full wrap around the core that holds the primary and exits on the same side that it entered, then it is a full turn.? If you measure the open circuit voltage of the Weller soldering gun tube, it should be approximately a quarter volt.? That tube allows about 100 VA to be transformed to about 400 amps @ 0.25 volt! ? As long as you can fit an insulated wire between the bobbin and the laminations and make a full turn as in above then you can determine the turns-per-volt of any power?transformer.? I prefer 10 turns, make the measurement and then divide it by 10 but you can do as you like.? You must have a transformer or two in your junk-box so it should be easy to verify this procedure. ? Typically one strips off only the secondary windings and keeps the primary intact.? Knowing the voltage produced by a high current heater winding and counting the turns will give the same result for the turns-per-volt of that particular transformer.? Then wind as many turns as needed to get the output voltage wanted in the secondary windings.? This was one of the first lab experiments in college for transformers in AC circuits. Regards, Jim -- don??? va3drl |
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Re: HT-37 transformer failure due to rapid STBY-->OFF-->STBY
开云体育Jim, by now this stuff might have been clarified, so there is no need to continue reading, but if not I am just going to try to explain my understanding of his ?post He said: These surges occur only when the last cycle before turn-off is of the same polarity as the first cycle after turn-on.? I read this to mean that there is a 50/50 chance as to the polarity just before the last current, and the first image showed the thump situation. This is consistent with the explanation that remanence and saturation are the causes.? The core is left magnetized with one polarization when the transmitter is turned off, and the first cycle once turned on seeks to increase that magnetization further.? Since it hits the limit, there is no further conversion to magnetism available, so the current is limited only by the resistance in the primary, the current-sampling resistor, the wiring in the transmitter, and the wiring from the outlet to the circuit breaker panel. ?Makes sense to me ? Sometimes, there's no such surge and the measurement looks like this: ??---IMAGE here I read this to mean that ?this is the “no thump” situation. My interpretation was that ?the core was left with exactly the right “negative” flux so that the positive half sinusoid swung the flux the exact amount “positive” such that, the core would then swing the same amount positive and negative, so we don’t see positive saturation or negative, we just see the resistive load. ? Sorry I have now lost the image number? 58 and ?? maybe From: [email protected] [mailto:[email protected]] On Behalf Of Jim Whartenby via groups.io
Sent: Thursday, August 8, 2024 11:11 AM To: [email protected] Subject: Re: [HallicraftersRadios] HT-37 transformer failure due to rapid STBY-->OFF-->STBY ? Halden The second o'scope image is exactly what I would expect to see from an SSR switch at turn on.? At the voltage zero crossing, the current is always at a maximum with voltage leading the current by 90 degrees.? The initial buildup of the transformer's magnetic field requires a slug of current, more so if the transformer's core was left magnetized when the voltage was of the opposite polarity.? The SSR will always force this condition at every turn on.? This is the repeated transformer stress mentioned in previous posts.? The slug of current causes that thump heard as the transformer's primary coil tries to move in reaction to the very high start up current. ? What conditions are different in the third o'scope image?? This contradicts what is shown in the second image.? Would expect this to happen when measuring the E&I characteristics of a resistance, not a reactance. Regards, Jim _._,_._,_ -- don??? va3drl |
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Re: HT-37 transformer failure due to rapid STBY-->OFF-->STBY
OK, back to the beginning. Some of Halden's scope images show the transformer's primary current in phase with the voltage across the primary, a few show a 90 degree phase difference with voltage leading current by 90 degrees.? Which is right? Jim Logic: Method used to arrive at the wrong conclusion, with confidence.? Murphy
On Sunday, August 11, 2024 at 05:12:06 PM CDT, don Root <drootofallevil@...> wrote:
Guys; ?Jim and Mike, ?a reminder. there might be some truths in here, but it seems you are going far off the intent of this topic. The space would be better served by getting US back closer to Halden’s topic and tests. ? From: [email protected] [mailto:[email protected]] On Behalf Of Jim Whartenby via groups.io
Sent: Sunday, August 11, 2024 2:08 PM To: [email protected] Subject: Re: [HallicraftersRadios] HT-37 transformer failure due to rapid STBY-->OFF-->STBY ? Mike Watch the video.? By instantaneous I mean much faster then the speed of an electron and approaching the speed of light.? By approaching the speed of light I mean much faster then 50% of C which is faster then anything with mass can approach. Jim ? ??? -- don??? va3drl |
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Re: HT-37 transformer failure due to rapid STBY-->OFF-->STBY
Don In a transformer, a half turn starts on one side of the laminated core and exits on the other.? Since the Weller has that plated copper tube entering the core on one side and exiting the core on the other, it is by definition, a half turn.? It does not matter if the tube wraps around the outside of the lamination, it is still a half turn through the core.? If a winding makes one full wrap around the core that holds the primary and exits on the same side that it entered, then it is a full turn.? If you measure the open circuit voltage of the Weller soldering gun tube, it should be approximately a quarter volt.? That tube allows about 100 VA to be transformed to about 400 amps @ 0.25 volt! As long as you can fit an insulated wire between the bobbin and the laminations and make a full turn as in above then you can determine the turns-per-volt of any power?transformer.? I prefer 10 turns, make the measurement and then divide it by 10 but you can do as you like.? You must have a transformer or two in your junk-box so it should be easy to verify this procedure. Typically one strips off only the secondary windings and keeps the primary intact.? Knowing the voltage produced by a high current heater winding and counting the turns will give the same result for the turns-per-volt of that particular transformer.? Then wind as many turns as needed to get the output voltage wanted in the secondary windings.? This was one of the first lab experiments in college for transformers in AC circuits. Regards, Jim Logic: Method used to arrive at the wrong conclusion, with confidence.? Murphy
On Sunday, August 11, 2024 at 02:53:16 PM CDT, don Root <drootofallevil@...> wrote:
Don Most , if not all, power transformers we use in radios are close to half a volt-per-turn in any winding, primary or secondary.?My guess is 40 VA to 100 VA is almost the same for all receivers ?= same core X-C, so needs same turns per volt but the HT-37 takes ?100 VA? just for 6.3 and 5V so ?? maybe Halden can look into it? ==? =? ??240 turns would be about right for a 120 volt primary.?? I don’t recall opening one up and counting turns, let alone rebuilding one, but did you count them on a bunch??????? ?Since the transformer secondaries are all open circuit, the only power drawn form the AC line is what is needed to generate the magnetic lines of force aka flux in the transformer's core.?? ? This changing flux generated by the primary winding also cuts the primary winding in such a way to generate a voltage to oppose the AC line voltage aka a counter EMF.? So in the end, only a miniscule current flows from the AC line through the primary winding.? Just enough line current flows to support the flux needed to generate the counter EMF and account for the power losses in copper and iron.? This counter EMF is in anything with a winding which gets it power form the AC line: transformers, relays, motors, inductors, whatever. ? It should be easy for you to verify the turns-per-volt of any power transformer.? All one needs is some thin magnet wire to wind around the core and something to measure the resulting voltage.?I don’t know that your wording is complete, but ya ..If only my fingers could feel that little wire. And then what would I do with that information? But it would be good to know if you are going to use a core for to build a new transformer. Note, you can have nothing smaller then a half turn coil.?? I don’t know how to make a half turn that does anything, but it you have half ?a turn or a quarter? or whatever, and connect a meter somehow as far as the core is concerned you end up with a circuit that is no turn or 1 turn , and …you need twisted leads all the way to the ?“half turn”, but then the leads have to go ? turn left and a ? turn right forming the rest of 1 turn, or maybe no turn.???? Like what is used in a Weller soldering gun heating element winding. The tip might be half a circle, but the other ? circle is around ?the core making one turn in all. ???However they do make half turns etc for instrument transformers by “drilling” a hole in the core so that this turn sees only ? of the total flux; this part turn is just to get the exact voltage ratio that they want. Now that we have been switched onto another siding, I don’t know why we are sitting here. ? From: [email protected] [mailto:[email protected]] On Behalf Of Jim Whartenby via groups.io
Sent: Sunday, August 11, 2024 1:17 AM To: [email protected] Subject: Re: [HallicraftersRadios] HT-37 transformer failure due to rapid STBY-->OFF-->STBY ? Don Most , if not all, power transformers we use in radios are close to half a volt-per-turn in any winding, primary or secondary.? 240 turns would be about right for a 120 volt primary.? Since the transformer secondaries are all open circuit, the only power drawn form the AC line is what is needed to generate the magnetic lines of force aka flux in the transformer's core.?? ? This changing flux generated by the primary winding also cuts the primary winding in such a way to generate a voltage to oppose the AC line voltage aka a counter EMF.? So in the end, only a miniscule current flows from the AC line through the primary winding.? Just enough line current flows to support the flux needed to generate the counter EMF and account for the power losses in copper and iron.? This counter EMF is in anything with a winding which gets it power form the AC line: transformers, relays, motors, inductors, whatever. ? It should be easy for you to verify the turns-per-volt of any power transformer.? All one needs is some thin magnet wire to wind around the core and something to measure the resulting voltage.? Note, you can have nothing smaller then a half turn coil.? Like what is used in a Weller soldering gun heating element winding. Regards, Jim Logic: Method used to arrive at the wrong conclusion, with confidence.? Murphy ? ? On Saturday, August 10, 2024 at 10:14:54 PM CDT, don Root <drootofallevil@...> wrote: ? ? Jim ??Without going back I believe ?WAS ?talking about Halden's measurements of the HT-37 power transformer A question for you: If a transformer has about 240 turns of wire in the primary which amounts to perhaps 5 ohms of resistance, how much current will it draw when connected to 120 volts, 60 cycles with all secondaries open circuit?? ? JIM absolutely no idea unless at least you say what voltage it was designed for. Assuming it was designed for 120/60Hz we still don’t know. It all depends on the core steel itself ?and the physical sizes. Given the same steel? and sizes of laminations ?it now ?depends on how many laminations and ?how hard they decide to push the steel up the B-H curve [ not too too much saturation] at designed voltage. ?The ohms ?have little to do with it until the transformer is loaded.? It seems to me if you reduce the turns, you have to increase the core X-C area etc etc.. but if you make a desirable transformer the magnetizing current will be less than say 30% but that is loose. Since 1870’s the DOE mandated lower more efficient transformers [ for really big transformers] so core loss became critical and they finally started ?research etc and making high cost Grain oriented electrical Steel which? so now maybe all new transformers are more efficient than before. ? If it were connected to DC, the current would be perhaps 24 amps but when connected to 60 cycles AC, what would you expect the primary winding current to be and why? On DC ?input, ?normal transformers are useless, they go straight into saturation. like what happens during Goemagnetic storms and long lines between transformers, I think the rest is up above.? If I understand your questions. Getting late so my wording might be off, typoes too. Hope that this is readable
? -- don??? va3drl |
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Re: HT-37 transformer failure due to rapid STBY-->OFF-->STBY
开云体育Guys; ?Jim and Mike, ?a reminder. there might be some truths in here, but it seems you are going far off the intent of this topic. The space would be better served by getting US back closer to Halden’s topic and tests. ? From: [email protected] [mailto:[email protected]] On Behalf Of Jim Whartenby via groups.io
Sent: Sunday, August 11, 2024 2:08 PM To: [email protected] Subject: Re: [HallicraftersRadios] HT-37 transformer failure due to rapid STBY-->OFF-->STBY ? Mike Watch the video.? By instantaneous I mean much faster then the speed of an electron and approaching the speed of light.? By approaching the speed of light I mean much faster then 50% of C which is faster then anything with mass can approach. Jim ? ??? -- don??? va3drl |
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Re: HT-37 transformer failure due to rapid STBY-->OFF-->STBY
开云体育
Jim, Mike too, Halden and all I hope most previous posts go into “quoted text” on line, but the bottom of emails will have redundant copies.. for good or bad. My stuff in green, the original still in black Mike, perhaps I have a problem reading your words, but I still can’t digest your post, the only thing I can say is that yes the R should help to dampen any transient ringing. Jim, I was just going to bypass this, but I have problems in places. If you are saying that a pure reactance has a 90 degree phase difference between E&I and that any resistance will reduce this angle, then I agree.? The higher the resistance when compared to reactance, the more this effect.? In power transformers, the resistance is very small compared to reactance so it's effect is also small but it is still there, none the less.? Ok? This idea of a surge in an inductor is just plain physics. Ok, but some is not so “plain”, and don’t forget anything.? The closer to the zero voltage crossover point, the higher the current surge Ok often but. since they are separated by 90 degrees. That does not read well to me. To come up with the answer, you have to take the integral of the voltage over time, which is most easily seen as the area under the curve, and this first excursion can be well over 90 degrees, depending on how you measure degrees when things go non-linear as can be seen in Halden’s images, and what you seem to be trying to say applies only if the core begins with no magnetism, as most simple analyses assume. The worst case is when the in addition to the zero voltage crossover, the magnetic pole of the laminations has to be reversed. Perhaps words get in the way of my understanding of this, but there will be little saturation if the magnetism has been “negative”, and is now driven “positive”, but it will saturate quickly if it is “positive” is driven more “positive”, etc. I am thankful for Halden’s tests which seem to show much of this, however after any switch “off” is complete to current zero the flux left in the core seems to be a hard thing to calculate, but these days you can put a hall probe in the core if you really want to know, this aiming too far off topic.? It is evidently easier to picture the surge in a filter capacitor then in an inductor. Maybe, but it is far to general for me to make a comparison.? The only reason for the concern in a filter capacitor was the inability of a vacuum tube rectifier to handle a high surge current without damage.?I can’t see any connection to the topic Solid state rectifiers have eliminated this concern since they have the ability to support a 30 amp or more initial surge current. I can’t see any connection to the original topic, but when a topic for HT-37 modifications comes up it would be relevant. As to the rest of the words, I don’t understand them, and I don’t understand why they are here. Most of us believe that a current is the movement of electrons.? Maxwell (and thanks to Heaviside) has a different opinion.? What actually happens is mind bending.? Electrons move too slow to carry a current but the charge on the surface of the wire does travel at the speed of light.? See: This is a basic tutorial on Maxwell without the math which I would not understand either!? Instead of solving Maxwell's equations for every circuit, we can use a lumped element model which we call Ohm's Law. ? So the magnetization in the inductor happens at the speed of light just as the charge does on the surface of the wire.? Like I said, mind blowing! Regards, Jim Logic: Method used to arrive at the wrong conclusion, with confidence.? Murphy ? ? On Sunday, August 11, 2024 at 08:54:30 AM CDT, Mike Feher <n4fs@...> wrote: ?? From: [email protected] [mailto:[email protected]] On Behalf Of Jim Whartenby via groups.io
Sent: Sunday, August 11, 2024 12:40 PM To: [email protected] Subject: Re: [HallicraftersRadios] HT-37 transformer failure due to rapid STBY-->OFF-->STBY ? Mike If you are saying that a pure reactance has a 90 degree phase difference between E&I and that any resistance will reduce this angle, then I agree.? The higher the resistance when compared to reactance, the more this effect.? In power transformers, the resistance is very small compared to reactance so it's effect is also small but it is still there, none the less. ? This idea of a surge in an inductor is just plain physics.? The closer to the zero voltage crossover point, the higher the current surge since they are separated by 90 degrees.? The worst case is when the in addition to the zero voltage crossover, the magnetic pole of the laminations has to be reversed. ? It is evidently easier to picture the surge in a filter capacitor then in an inductor.? The only reason for the concern in a filter capacitor was the inability of a vacuum tube rectifier to handle a high surge current without damage.? Solid state rectifiers have eliminated this concern since they have the ability to support a 30 amp or more initial surge current. ? Most of us believe that a current is the movement of electrons.? Maxwell (and thanks to Heaviside) has a different opinion.? What actually happens is mind bending.? Electrons move too slow to carry a current but the charge on the surface of the wire does travel at the speed of light.? See: This is a basic tutorial on Maxwell without the math which I would not understand either!? Instead of solving Maxwell's equations for every circuit, we can use a lumped element model which we call Ohm's Law. ? So the magnetization in the inductor happens at the speed of light just as the charge does on the surface of the wire.? Like I said, mind blowing! Regards, Jim Logic: Method used to arrive at the wrong conclusion, with confidence.? Murphy ? ? On Sunday, August 11, 2024 at 08:54:30 AM CDT, Mike Feher <n4fs@...> wrote: ? ? Hi Jim – While in most transformers it is minimal, the primary resistance also draws current, so it is the sum of the two for total. Actually, the R might dampen the input surge some. Remember, at T equal to zero, only the R is present as the inductance is an open circuit until magnetization takes place. 73 – Mike ? Mike B. Feher, N4FS 89 Arnold Blvd. Howell NJ 07731 908-902-3831 ? From: [email protected] <[email protected]> On Behalf Of Jim Whartenby via groups.io ? Don Most , if not all, power transformers we use in radios are close to half a volt-per-turn in any winding, primary or secondary.? 240 turns would be about right for a 120 volt primary.? Since the transformer secondaries are all open circuit, the only power drawn form the AC line is what is needed to generate the magnetic lines of force aka flux in the transformer's core.?? ? This changing flux generated by the primary winding also cuts the primary winding in such a way to generate a voltage to oppose the AC line voltage aka a counter EMF.? So in the end, only a miniscule current flows from the AC line through the primary winding.? Just enough line current flows to support the flux needed to generate the counter EMF and account for the power losses in copper and iron.? This counter EMF is in anything with a winding which gets it power form the AC line: transformers, relays, motors, inductors, whatever. ? It should be easy for you to verify the turns-per-volt of any power transformer.? All one needs is some thin magnet wire to wind around the core and something to measure the resulting voltage.? Note, you can have nothing smaller then a half turn coil.? Like what is used in a Weller soldering gun heating element winding. Regards, Jim ?? -- don??? va3drl |
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Re: HT-37 transformer failure due to rapid STBY-->OFF-->STBY
开云体育Don Most , if not all, power transformers we use in radios are close to half a volt-per-turn in any winding, primary or secondary.?My guess is 40 VA to 100 VA is almost the same for all receivers ?= same core X-C, so needs same turns per volt but the HT-37 takes ?100 VA? just for 6.3 and 5V so ?? maybe Halden can look into it? ==? =? ??240 turns would be about right for a 120 volt primary.?? I don’t recall opening one up and counting turns, let alone rebuilding one, but did you count them on a bunch??????? ?Since the transformer secondaries are all open circuit, the only power drawn form the AC line is what is needed to generate the magnetic lines of force aka flux in the transformer's core.?? ? This changing flux generated by the primary winding also cuts the primary winding in such a way to generate a voltage to oppose the AC line voltage aka a counter EMF.? So in the end, only a miniscule current flows from the AC line through the primary winding.? Just enough line current flows to support the flux needed to generate the counter EMF and account for the power losses in copper and iron.? This counter EMF is in anything with a winding which gets it power form the AC line: transformers, relays, motors, inductors, whatever. ? It should be easy for you to verify the turns-per-volt of any power transformer.? All one needs is some thin magnet wire to wind around the core and something to measure the resulting voltage.?I don’t know that your wording is complete, but ya ..If only my fingers could feel that little wire. And then what would I do with that information? But it would be good to know if you are going to use a core for to build a new transformer. Note, you can have nothing smaller then a half turn coil.?? I don’t know how to make a half turn that does anything, but it you have half ?a turn or a quarter? or whatever, and connect a meter somehow as far as the core is concerned you end up with a circuit that is no turn or 1 turn , and …you need twisted leads all the way to the ?“half turn”, but then the leads have to go ? turn left and a ? turn right forming the rest of 1 turn, or maybe no turn.???? Like what is used in a Weller soldering gun heating element winding. The tip might be half a circle, but the other ? circle is around ?the core making one turn in all. ???However they do make half turns etc for instrument transformers by “drilling” a hole in the core so that this turn sees only ? of the total flux; this part turn is just to get the exact voltage ratio that they want. Now that we have been switched onto another siding, I don’t know why we are sitting here. ? From: [email protected] [mailto:[email protected]] On Behalf Of Jim Whartenby via groups.io
Sent: Sunday, August 11, 2024 1:17 AM To: [email protected] Subject: Re: [HallicraftersRadios] HT-37 transformer failure due to rapid STBY-->OFF-->STBY ? Don Most , if not all, power transformers we use in radios are close to half a volt-per-turn in any winding, primary or secondary.? 240 turns would be about right for a 120 volt primary.? Since the transformer secondaries are all open circuit, the only power drawn form the AC line is what is needed to generate the magnetic lines of force aka flux in the transformer's core.?? ? This changing flux generated by the primary winding also cuts the primary winding in such a way to generate a voltage to oppose the AC line voltage aka a counter EMF.? So in the end, only a miniscule current flows from the AC line through the primary winding.? Just enough line current flows to support the flux needed to generate the counter EMF and account for the power losses in copper and iron.? This counter EMF is in anything with a winding which gets it power form the AC line: transformers, relays, motors, inductors, whatever. ? It should be easy for you to verify the turns-per-volt of any power transformer.? All one needs is some thin magnet wire to wind around the core and something to measure the resulting voltage.? Note, you can have nothing smaller then a half turn coil.? Like what is used in a Weller soldering gun heating element winding. Regards, Jim Logic: Method used to arrive at the wrong conclusion, with confidence.? Murphy ? ? On Saturday, August 10, 2024 at 10:14:54 PM CDT, don Root <drootofallevil@...> wrote: ? ? Jim ??Without going back I believe ?WAS ?talking about Halden's measurements of the HT-37 power transformer A question for you: If a transformer has about 240 turns of wire in the primary which amounts to perhaps 5 ohms of resistance, how much current will it draw when connected to 120 volts, 60 cycles with all secondaries open circuit?? ? JIM absolutely no idea unless at least you say what voltage it was designed for. Assuming it was designed for 120/60Hz we still don’t know. It all depends on the core steel itself ?and the physical sizes. Given the same steel? and sizes of laminations ?it now ?depends on how many laminations and ?how hard they decide to push the steel up the B-H curve [ not too too much saturation] at designed voltage. ?The ohms ?have little to do with it until the transformer is loaded.? It seems to me if you reduce the turns, you have to increase the core X-C area etc etc.. but if you make a desirable transformer the magnetizing current will be less than say 30% but that is loose. Since 1870’s the DOE mandated lower more efficient transformers [ for really big transformers] so core loss became critical and they finally started ?research etc and making high cost Grain oriented electrical Steel which? so now maybe all new transformers are more efficient than before. ? If it were connected to DC, the current would be perhaps 24 amps but when connected to 60 cycles AC, what would you expect the primary winding current to be and why? On DC ?input, ?normal transformers are useless, they go straight into saturation. like what happens during Goemagnetic storms and long lines between transformers, I think the rest is up above.? If I understand your questions. Getting late so my wording might be off, typoes too. Hope that this is readable
? -- don??? va3drl |
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Re: HT-37 transformer failure due to rapid STBY-->OFF-->STBY
Mike Watch the video.? By instantaneous I mean much faster then the speed of an electron and approaching the speed of light.? By approaching the speed of light I mean much faster then 50% of C which is faster then anything with mass can approach. Jim Logic: Method used to arrive at the wrong conclusion, with confidence.? Murphy
On Sunday, August 11, 2024 at 12:54:08 PM CDT, Mike Feher <n4fs@...> wrote:
Jim – ? Seems you have a tendency to make things more difficult than need be. The problem is that no electrical physical element is pure. You have inherent resistance of the wire and distributive capacitance between winding. Of course the opposite is true for an capacitor. You have ESR and you have inductance, the amount of which is dependent on the capacitor type. Also, other than an EM wave, nothing travels at the speed of light. Capacitors and inductors both have a time constant associated with them. Nothing is instantaneous. As I said, at T=0 and inductor is open and a capacitor is a short. – Mike ? Mike B. Feher, N4FS 89 Arnold Blvd. Howell NJ 07731 908-902-3831 ? From: [email protected] <[email protected]> On Behalf Of Jim Whartenby via groups.io
Sent: Sunday, August 11, 2024 12:40 PM To: [email protected] Subject: Re: [HallicraftersRadios] HT-37 transformer failure due to rapid STBY-->OFF-->STBY ? Mike If you are saying that a pure reactance has a 90 degree phase difference between E&I and that any resistance will reduce this angle, then I agree.? The higher the resistance when compared to reactance, the more this effect.? In power transformers, the resistance is very small compared to reactance so it's effect is also small but it is still there, none the less. ? This idea of a surge in an inductor is just plain physics.? The closer to the zero voltage crossover point, the higher the current surge since they are separated by 90 degrees.? The worst case is when the in addition to the zero voltage crossover, the magnetic pole of the laminations has to be reversed. ? It is evidently easier to picture the surge in a filter capacitor then in an inductor.? The only reason for the concern in a filter capacitor was the inability of a vacuum tube rectifier to handle a high surge current without damage.? Solid state rectifiers have eliminated this concern since they have the ability to support a 30 amp or more initial surge current. ? Most of us believe that a current is the movement of electrons.? Maxwell (and thanks to Heaviside) has a different opinion.? What actually happens is mind bending.? Electrons move too slow to carry a current but the charge on the surface of the wire does travel at the speed of light.? See: This is a basic tutorial on Maxwell without the math which I would not understand either!? Instead of solving Maxwell's equations for every circuit, we can use a lumped element model which we call Ohm's Law. ? So the magnetization in the inductor happens at the speed of light just as the charge does on the surface of the wire.? Like I said, mind blowing! Regards, Jim Logic: Method used to arrive at the wrong conclusion, with confidence.? Murphy ? ? On Sunday, August 11, 2024 at 08:54:30 AM CDT, Mike Feher <n4fs@...> wrote: ? ? Hi Jim – While in most transformers it is minimal, the primary resistance also draws current, so it is the sum of the two for total. Actually, the R might dampen the input surge some. Remember, at T equal to zero, only the R is present as the inductance is an open circuit until magnetization takes place. 73 – Mike ? Mike B. Feher, N4FS 89 Arnold Blvd. Howell NJ 07731 908-902-3831 _,_ |
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SR-150 VFO info
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SR-150 information.
I have had several contacts lately about problems with the VFO in the SR-150. I put together a document specifically addressing issues with the VFO, how to test subsystems and alignment.
I have published it on my website. It can be downloaded @
Walt Cates, WD0GOF
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Re: HT-37 transformer failure due to rapid STBY-->OFF-->STBY
Mike If you are saying that a pure reactance has a 90 degree phase difference between E&I and that any resistance will reduce this angle, then I agree.? The higher the resistance when compared to reactance, the more this effect.? In power transformers, the resistance is very small compared to reactance so it's effect is also small but it is still there, none the less. This idea of a surge in an inductor is just plain physics.? The closer to the zero voltage crossover point, the higher the current surge since they are separated by 90 degrees.? The worst case is when the in addition to the zero voltage crossover, the magnetic pole of the laminations has to be reversed. It is evidently easier to picture the surge in a filter capacitor then in an inductor.? The only reason for the concern in a filter capacitor was the inability of a vacuum tube rectifier to handle a high surge current without damage.? Solid state rectifiers have eliminated this concern since they have the ability to support a 30 amp or more initial surge current. Most of us believe that a current is the movement of electrons.? Maxwell (and thanks to Heaviside) has a different opinion.? What actually happens is mind bending.? Electrons move too slow to carry a current but the charge on the surface of the wire does travel at the speed of light.? See: This is a basic tutorial on Maxwell without the math which I would not understand either!? Instead of solving Maxwell's equations for every circuit, we can use a lumped element model which we call Ohm's Law. So the magnetization in the inductor happens at the speed of light just as the charge does on the surface of the wire.? Like I said, mind blowing! Regards, Jim Logic: Method used to arrive at the wrong conclusion, with confidence.? Murphy
On Sunday, August 11, 2024 at 08:54:30 AM CDT, Mike Feher <n4fs@...> wrote:
Hi Jim – While in most transformers it is minimal, the primary resistance also draws current, so it is the sum of the two for total. Actually, the R might dampen the input surge some. Remember, at T equal to zero, only the R is present as the inductance is an open circuit until magnetization takes place. 73 – Mike ? Mike B. Feher, N4FS 89 Arnold Blvd. Howell NJ 07731 908-902-3831 ? From: [email protected] <[email protected]> On Behalf Of Jim Whartenby via groups.io
Sent: Sunday, August 11, 2024 1:17 AM To: [email protected] Subject: Re: [HallicraftersRadios] HT-37 transformer failure due to rapid STBY-->OFF-->STBY ? Don Most , if not all, power transformers we use in radios are close to half a volt-per-turn in any winding, primary or secondary.? 240 turns would be about right for a 120 volt primary.? Since the transformer secondaries are all open circuit, the only power drawn form the AC line is what is needed to generate the magnetic lines of force aka flux in the transformer's core.?? ? This changing flux generated by the primary winding also cuts the primary winding in such a way to generate a voltage to oppose the AC line voltage aka a counter EMF.? So in the end, only a miniscule current flows from the AC line through the primary winding.? Just enough line current flows to support the flux needed to generate the counter EMF and account for the power losses in copper and iron.? This counter EMF is in anything with a winding which gets it power form the AC line: transformers, relays, motors, inductors, whatever. ? It should be easy for you to verify the turns-per-volt of any power transformer.? All one needs is some thin magnet wire to wind around the core and something to measure the resulting voltage.? Note, you can have nothing smaller then a half turn coil.? Like what is used in a Weller soldering gun heating element winding. Regards, Jim |
don Root
Jim Whartenby
waltcates